Antiscreening versus screening excitations for low-energy ion-ion collisions in dense plasmas using the screened hyperbolic-orbit trajectory method

Plasma screening effects are investigated on antiscreening and screening channels for excitation of a one-electron target ion by a one-electron projectile ion in dense plasmas. In weakly coupled plasmas, the ion-ion interaction potential is given by the nonspherical Debye-Hückel model. The semiclassical screened hyperbolic-orbit trajectory method is applied to the path of the projectile ion in order to investigate the variation of the antiscreening and screening transition probabilities as functions of the impact parameter and collision energy. The results show that the antiscreening transition probability is always greater than the screening transition probability. It is found that the plasma screening effect on the antiscreening transition probability is more effective than that on the screening transition probability. The maximum position of the transition probability is getting closer to the target core with increasing projectile energy. The plasma screening effect on the antiscreening excitation cross section is also found to be stronger than that on the screening excitation cross section.